Effect of Sex and Breed on HSPA1A, Blood Stress Indicators and Meat Quality of Lambs

SIMPLE SUMMARY: Livestock rearing and slaughter methods have received much criticism from various sub-divisions of the society over the years. The root of this criticism is attributed to the growing demand for meat produced from humanely handled animals and issues associated with meat quality and traceability. Ethical arguments around the slaughtering of animals has had less impact on the demand of animal products, however public concern about the welfare of slaughter animals and pre-slaughter stress have been the topical issues. Research on the impact of pre-slaughter stress on animal welfare and meat quality, mostly in pigs and cattle has been well documented. However, there is still paucity of information on the biomarkers of stress in lambs in response to pre-slaughter and its overall impact on meat quality. Therefore, the objective of this study was to examine sex and breed effects on heat shock proteins, blood stress indicators and meat quality attributes from lambs slaughtered at commercial abattoir. ABSTRACT: The objective of this study was to examine sex and breed effects on heat shock protein 70 (HSPA1A), blood stress indicators and meat quality attributes of lambs. A hundred male and female lambs from the Dorper (n = 50) and Merino (n = 50) breeds were used in this study. Breed and sex had a significant (p < 0.05) effect on the levels of plasma HSPA1A and lactate; where the Merino lambs had higher levels than Dorper. The female lambs had higher levels of plasma HSPA1A than male lambs. Significant sex and breed interactions (p < 0.05) on the levels of plasma HSPA1A were seen. Females had higher (p < 0.05) pHu than males. Dorper lambs had higher (p < 0.05) pH(45), meat lightness, thawing loss and tougher meat the Merino breed. Significant correlations were found amongst plasma stress indicators and meat quality attributes. The results indicate that female lambs were more stressed by the pre-slaughter period than males, while the Merino had a higher physiological stress response compared to the Dorper. However, the Dorper breed produced tougher meat.